Authorized electronic surveillance is an indispensable tool used by various law enforcement entities in the fight against crime and terrorism. In 1994, in order to preserve the ability of law enforcement entities to conduct electronic surveillance with the continuing advances in the telecommunications industry, Congress passed the Communications Assistance for Law Enforcement Act (CALEA). The law defines the statutory obligations of telecommunication carriers to assist law enforcement entities with properly authorized electronic surveillance. At a high level, CALEA requires carriers to design or modify their systems to ensure that the appropriate level of electronic surveillance may be performed. Specifically, CALEA ensures that telecommunications carriers will have the necessary capability, and sufficient capacity, to assist law enforcement entities in various types of electronic surveillance regardless of the telecommunications carriers' specific systems or services.
Electronic surveillance typically refers to either the interception of call content, commonly referred to as full wiretaps, and/or the interception of call-identifying information, commonly referred to as partial wiretaps, through the use of pen registers and/or trap and trace devices. Full wire taps allow the interception of the call content and allow the law enforcement entity to hear all of the conversations that occur. In contrast, a partial wiretap only allows the law enforcement entity to find what numbers have been dialed, incoming calls, and the like.
As technology advances, communication carriers are required to provide support for electronic surveillance. In Voice over Internet Protocol (VoIP) networks, for example, one solution has been to specify the P-DCS-LAES header to signal the need to send a copy of signaling, and optionally content, as the call is setup. Typically this type of mechanism for marking an endpoint as requiring lawfully authorized surveillance is undefined and proprietary. Communication carriers have used Private Session Initiation Protocol (SIP) proxy-to-proxy extensions to support the packet cable distributed call signaling architecture. One disadvantage to this approach, however, is that it does not provide any mechanism for identifying a surveillance requestor as being authorized. Another common method used in some VoIP networks is to route all the media packets and signaling through a centralized location which then determines which media packets and signaling information should be monitored and reported to the law enforcement agency.
Thus, a need exists for systems and methods for collecting call signaling and event notification information of a monitored user based on an authorized surveillance request.